1. Kingdom Archaebacteria & Kingdom Eubacteria
Chapter 24

2. Evolution & Classification
Section 24-1

3. Evolution & Classification
Bacteria are microscopic prokaryotes, organisms that lack a cell nucleus
Unlike most organisms, bacteria have few morphological differences

4. Characteristics of Prokaryotes
Do NOT have a membrane-bound nucleus
Do have a cell membrane, but do NOT have membrane bound organelles
Have ribosomes that are different from those of eukaryotes
Smaller than the smallest eukaryotes
Unicellular

5. Kingdoms of Bacteria
There are two kingdoms of bacteria separated based on the ribosomal RNA sequences.
Kingdom Archeabacteria – the “ancient” bacteria that live in very harsh environments
Kingdom Eubacteria – the “true” bacteria that we consider to be germs

6. Kingdom Archaebacteria
Do not have peptidoglycan, a protein-carbohydrate found in the cell walls of eubacteria
Live in extreme environments so that is how they are classified

7. Phylum Methanogens Live in anaerobic, oxygen free environments
Produce methane gas by converting H2 and CO2 into CH4, this is a form of chemosynthesis
Live in swamps, sewage, marshes, animal digestive tracts.

8. Phylum Thermoacidophiles
Can live in water that is extremely hot and acidic
Found in hot springs or hydrothermal vents
Use the heat and acids of their habitat to produce food by chemosynthesis

9. Phylum Extreme Halophiles
Live in extremely salty conditions
Found in the Great Salt Lake of Utah, Dead Sea, and Chaplin Lake
Use the salt in their environment for energy, a form of chemosynthesis.

10. Kingdom Eubacteria Have peptidoglycan in their cell walls
Classified on shape
Classified on how they react to Gram staining

11. Eubacteria Shapes Eubacteria have three different shapes
Bacilli – rod shaped
Cocci – sphere shaped
Spirilla – spiral shaped

12. Gram Staining
A staining technique that divides bacteria into gram-positive and gram-negative
The technique involves staining bacteria with a purple dye and iodine and rinsing with alcohol then restained with a pink dye

13. Gram Positive
If the cell retains the purple color they are gram-positive and they have a thick peptidoglycan layer in their cell wall
They are usually beneficial
We usually use them to make antibiotics, which kill other gram-positive bacteria

14. Gram Negative
If the cell does not retain the purple dye but takes on the pink dye it is gram-negative
They have an extra layer of lipid on the outside of the cell wall
They tend to resist antibiotics

15. Phylum Cyanobacteria They are gram-negative bacteria
They perform photosynthesis and release oxygen so they are aerobic
Grow in long filaments of cells
Some have heterocysts, special cells that contain enzymes that can fix atmospheric nitrogen

16. Phylum Spirochetes Gram-negative bacteria
Spiral shaped heterotrophic bacteria
Most are aerobic but some are anaerobic
Move by corkscrew rotation

17. Phylum Gram-positive Most are gram-positive to Gram stain
They are found in diseases and food materials
They can be filamentous or single celled

18. Phylum Proteobacteria
The largest and most diverse phylum
There are three subphylums
Enteric
Chemoautotrophic
Nitrogen-fixing

19. Enteric Bacteria Gram-negative heterotrophic bacteria
Inhabit intestinal tracts
Live in aerobic and anaerobic conditions

20. Chemoautotrophs Gram-negative bacteria
Extract energy from oxidizing minerals so by chemosynthesis

21. Nitrogen-fixing Gram-negative bacteria
Usually grow symbiotically in root nodules of plants
Able to convert atmospheric nitrogen into useful compounds such as ammonia and nitrates
Need them to build amino acids for the building of proteins

22. Biology of Bacteria
Section 24-2

23. Bacteria Structure Bacteria are typically composed of Cell wall
Cell membrane
Cytoplasm with ribosomes
Chromosome

24. (a) Cell Wall Eubacteria cell walls are made of peptidoglycan
Archeabacteria cell walls are composed of a different compound related to cellulose and chitin

25. (b) Cell Membrane The cell membrane is composed of a lipid bilayer
The cell membrane has special enzymes for carrying out cellular respiration and photosynthesis
The membrane of photosynthetic bacteria have folds called thylakoids like those in chloroplasts

26. (c) Cytoplasm Bacterial cells do not have membrane bound organelles
The cytoplasm of bacterial cells is made of a viscous solution of ribosomes and DNA

27. (d) Capsule Many bacteria have an outer covering called a capsule
The capsule is made of polysaccharides that cling to the surface of the cell and protect it against drying out or harsh chemicals
When a capsule consists of a fuzzy coat of sticky sugars, it is called a glycocalyx
The glycocalyx enables the bacteria to attach to the surface of host cells and tissues

28. (e) Pili
Pili are short, hairlike protein structures found on the surface of some species of bacteria
Pili help bacteria hold on to host cells and are also used for transfer of genetic material from one bacterium to another

29. (f) Endospores
When living conditions for the bacterium become unfavourable, some bacteria form special, dehydrated cells called endospores
Endospores consist of a thick outer covering that surrounds the cell’s DNA
When conditions become favorable the endospores break open and produce new bacterial cells

30. (g) Flagella
Many bacteria use flagella, whiplike structures that are used for movement
Those that do not have flagella use slime to glide through or a corkscrew rotation

31. Nutrition of Bacteria
Most bacteria are heterotrophs, they get their energy by consuming organic matter as a source of nutrition
Heterotrophs that feed on dead or decaying material are called saprophytes

32. Nutrition of Bacteria
Some bacteria are autotrophs, organisms capable of creating their own food energy
Photosynthetic – use sunlight to create food energy
Chemosynthetic – use the energy from oxidizing inorganic compounds to create food energy

33. Respiration in Bacteria
The type of cellular respiration is another difference between bacteria groups
Organisms that use oxygen during cellular respiration are aerobes.
Organisms that do not use oxygen during cellular respiration are anaerobes

34. Respiration in Bacteria
The presence or absence of oxygen in the environment is one way to distinguish between different bacteria
Bacteria called obligate aerobes cannot live without oxygen
Bacteria called obligate anaerobes cannot live in the presence of oxygen
Bacteria called facultative anaerobes can use oxygen when it is available but they do not depend on it

35. Reproduction in Bacteria
Most bacteria reproduce by binary fission, a process in which the chromosome replicates then the cell divides
Binary fission is a type of asexual reproduction

36. Genetic Recombination in Bacteria
Genetic recombination is a nonreproductive means by which bacteria acquire new combinations of genes
There are three special ways that bacteria exchange genes

37. Conjugation
The process of exchanging genetic material through cell to cell contact by a conjugation bridge from the pili
During conjugation DNA moves from one bacterium to another.

38. Transformation
The process by which bacteria cells pick up and incorporate DNA from dead bacteria cells.
They take up DNA from dead cells of the same or closely related species.

39. Transduction
The process by which the transfer of DNA from one bacteria to another is done by viruses.
Viruses called bacteriophages are used to carry DNA between cells

40. Bacteria and Humans
Section 24-3

41. Bacteria and Disease
The scientific study of disease is called pathology.
Bacteria that cause disease are called pathogens.
Some bacteria cause disease by producing toxins
Exotoxins are toxins that are secreted into the environment by the bacterium
Endotoxins are toxins are toxins that are released once the bacterium dies

42. Antibiotics
Antibiotics are drugs that fight bacteria by interfering with their cellular functions.
Many antibiotics are able to affect a wide variety of organisms, they are called broad spectrum antibiotics

43. Antibiotic Resistance
When a population of bacteria is exposed to an antibiotic, the most susceptible die. A few mutant bacteria are resistant to the antibiotic and continue to grow.
A resistant population then grows from these mutant bacteria and these new populations are antibiotic resistant
This results from over use of antibiotics.

44. Useful Bacteria
Bacteria are used in sewage treatment, and as decomposers, breaking down the remains of organic matter in dead plant and animal wastes. They are recyclers the return nutrients back to the environment.

45. Useful Bacteria Bacteria are useful in food production.
Bacteria help us make buttermilk, sour cream, yogurt, cottage cheese, sauerkraut and pickles.

46. Useful Bacteria
Bacteria are also used in industrial chemical production.
They produce organic chemicals and fuels.
They are used in mining of minerals
They are used as insecticides.

47. Useful Bacteria
Bacteria are used to help clean up environmental disaster caused by human such as chemical and oil spills.